Electronic equipment is often connected to other electronic equipment or to transmission facilities by means of multiconductor connectors. Such connectors are fabricated in mating pairs, one male and one female, which fit together to complete an electrical circuit between each of the conductors of one connector and the corresponding conductor of the other connector. For many applications, it is further necessary to provide electromagnetic and/or electrostatic shielding around the conductors to prevent the unwanted leakage of electromagnetic energy. Due to the necessity of providing all of these functions for a plurality of conductors, the design of such connectors has been complicated and required the assembly of many different parts, thereby increasing the cost and complexity of such connector assemblies. In some applications, the design of multiconductor connectors is aggravated by the need to provide a large number of such connectors in close proximity to each other. One such application is in a central connection box for local area data networks.
Many local area networks (LANs) have a ring architecture in which a plurality of stations are connected together in a ring. Messages are then transmitted from one station to another around the ring, using address information in the message header to deliver the messages to the proper destination. In such local area networks, such as within a single building, it is convenient to interconnect stations in a star network, with a central connection point, and with stations connected to such a central point by way of trunk transmission lines. In order to realize a ring network with a star architecture, it is necessary to route both an outgoing and an incoming trunk line between each station and the central point. At the central point, the trunk line terminations are interconnected into a serial ring. The various timing, framing and control circuits for enabling ring transmissions are also located at the central location. Finally, the central connection point is arranged to ensure ring transmission continuity in the absence of one or more stations from the star network. Such a central interconnection circuit is commonly known as a trunk access unit (TAU).
It will be noted that a trunk access unit includes many parts, both electronic and mechanical. The mechanical parts, and, in particular, the connectors which are used to connect the stations to the network must provide connections for the two trunk lines (four conductors) going to each station. Moreover, these connectors must provide bridging contacts which automatically connect the outgoing trunk line contacts to the incoming trunk line contacts when the station connector is unplugged from the TAU unit. connections must also be provided from the trunk line terminations to central control circuitry, preferable mounted on a printed circuit board (PCB) mounted in the TAU. Due to the high data rate normally used in such networks, the connector contacts must be shielded to prevent interference from signals leaking from the different trunk lines terminating in the TAU. As might be expected, these many functions are accommodated by connector structures and shielding structures which must be assembled in very particular relationships. In the prior art, these complicated structural relationships have been accommodated by painstaking assemblies of many small parts into subassemblies which, in turn are assembled into the final TAU assembly.
Electromagnetic shielding, for example, has been provided in the prior art by individual conductive shrouds assembled to surround each set of connector contacts and electrically mating with similar shielding shrouds forming part of the mating connector. These shrouds were typically assembled from piece parts mounted around each set of contacts, using fastening devices such as screws or rivets, a costly and time-consuming operation.
The connectors themselves typically comprise several non-conductive housing pieces into which are assembled the contact pins and around which the shielding shrouds are secured. Finally, all of the shielded connector assemblies are assembled into a cover panel closing one face of an electronics cabinet. It can thus be seen that the fabrication of shielded connectors for access to electronic equipment cabinets involves the assembly of large numbers of parts involving many separate subassembly steps, thereby increasing the cost and reducing the reliability of the resulting assemblage. Lower cost and more reliable electronic equipment cabinets (such as TAUs) would result from reducing the number of parts required to be assembled in order to provide such equipment cabinets.